(a) Field of the Invention
The invention relates to a USB plug for mobile flash drive and disposed, at an upper end of a pen shaft, thereby ensuring stability thereof when being inserted to a computer as well as enabling up-and-down adjustment of a refill within the pen shaft.
(b) Description of the Prior Art
Referring to FIG. 1 showing a common USB flash drive 100, wherein an USB plug 101 is inserted into a USB receptacle of a computer for accessing data. However, the flash drive 100 has no other purpose besides data storage, and is also rather awkward to carried along with. Industrialists have later developed a portable mobile disk-pen 200 as shown in FIG. 2, the pen comprises a USB plug 202 secured at a top end of a lower pen shaft 201. The USB plug 202 is stored in an upper pen sheath 203 when not in use, and an outer periphery of a refill 2011 at a lower end of the lower pen shaft 201 is fixed with a pen cap 204, such that the pen is both capable of writing and serving ap a mobile disk. Yet, this prior mobile disk-pen 200 has the following drawbacks when put to practice:    1. The USB plug 202 is installed at the lower pen shaft 201, which has a relatively longer body and is heavier because of the refill 2011 contained. As a result, the USB plug. 202 inevitably bears a relatively larger load when being inserted into a USB receptacle of a computer, and thus often leading to poor contact.    2. The USB plug 202 is joined with the lower pen shaft 201 via a connected single printed circuit board (PCB) 2021, and is therefore prone to wobble and again cause poor contact when being inserted into a USB receptacle of a computer.    3. The lower pen shaft 201 is secured with the USB plug 202 at an interior thereof, and thus no other refill can be replaced once the refill 2011 is consumed.    4. The outer periphery of the refill 2011 of the lower pen shaft 201 is necessarily accommodated within the pen cap 204, and the pen cap 204 is easily lost for that it is a separate part from the lower pen shaft 201.